Study of chilling and frost effects on Pomegranate (Punica granatum L.) in Yazd province

Arid lands of Iran, such as Yazd province, are the main regions for cultivating and economic production of pomegranate (Punica granatum L.). Low precipitation, dry and warm summer, cold winter and environmental stress, especially drought and frost, are ecological characteristics of these regions. Based on some important climatological indicators, coldness and frost in January 2008 was an unexpected event for Yazd province and other desert areas in Iran. Therefore, study of chilling and frost effects on pomegranate were conducted and continued for 2 years. Number of 180 pomegranate orchards were visited in the main centers of pomegranate production and questionnaires were completed by interviewing with gardeners. Data of these questionnaries were analyzed by using one sample T-test in SPSS. Simultaneously, 22 sites were selected in the main pomegranate production centers of Yazd province. In each site, 3 orchards with good, normal and weak quality of management and in each orchard 10 trees of prevailing cultivars, were randomly selected. In the next step, several factors such as intensity of damage on these trees were studied. Results show that due to coldness and frost in winter, most of pomegranate orchards were damaged. Sweet cultivars comparing to sour, white skin comparing to red skin, old trees comparing to young and gardens with weak management comparing to good management were effective on yield, fruitquality and tree damage. However, these frost resistances were broken in severe frosts and all cultivars of pomegranates were damaged. Roots were safe against frost and were produced plentiful shoots in all cases, even in regions with a minimum temperature of -24 C˚ in winter